Device To Increase Deposition Uniformity In Spatial ALD Processing Chamber

ABSTRACT

Susceptor assemblies comprising a susceptor with a top surface with a plurality of recesses and a bottom surface are described. A heater is positioned below the susceptor to heat the susceptor. A shield is positioned between the bottom surface of the susceptor and the heater. The shield increases deposition uniformity across the susceptor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. Provisional Application No.62/357,993, filed Jul. 2, 2016, the entire disclosure of which is herebyincorporated by reference herein.

TECHNICAL FIELD

The present disclosure relates generally to apparatus for depositingthin films. In particular, the disclosure relates to apparatus fordepositing thin films in a spatial atomic layer deposition batchprocessing chamber.

BACKGROUND

Wafer temperature uniformity is important in atomic layer deposition(ALD) processes. Deposition uniformity in spatial ALD batch processesreactors can be challenging where the wafer is positioned on a susceptormoving above an infrared heating system. Traditionally, for improvementof temperature uniformity, multi-zone heating is used. However, thesystems used for improved temperature uniformity are complex and thecost is proportional to the number of heating zones. Moreover, forspatial ALD systems with rotating susceptors it is very difficult toachieve good temperature distribution in the tangential direction and,as a result, leading and trailing edge temperatures are very difficultto homogenize with the rest of the wafer surface resulting innon-uniform deposition.

Therefore, there is a need in the art for apparatus and methods toincrease deposition uniformity in batch processing chambers.

SUMMARY

One or more embodiments of the disclosure are directed to susceptorassemblies comprising a susceptor with a top surface and a bottomsurface. The top surface has a plurality of recesses formed therein. Therecesses are sized to support a substrate during processing. A heater ispositioned below the susceptor to heat the susceptor. A shield ispositioned between the bottom surface of the susceptor and the heater.The shield increases deposition uniformity across the susceptor.

Additional embodiments of the disclosure are directed to susceptorassemblies comprising a susceptor with a top surface and a bottomsurface. The top surface has a plurality of recesses formed therein. Therecesses are sized to support a substrate during processing. A heater ispositioned below the susceptor to heat the susceptor. A shield ispositioned between the bottom surface of the susceptor and the heater.The shield comprises a plurality of shield segments. Each shield segmentis positioned in a region between the recesses and increasing depositionuniformity across the susceptor and is contoured to have a shape similarto a shape of the recesses and cover more of a leading edge of a recessthan a trailing edge of an adjacent recess. Each shield segment includesa plurality of openings therethrough. A plurality of suspension rodsconnects the susceptor and the shield. The suspension rods pass throughthe plurality of openings in the shield segments to support the shieldsegments and maintain a gap between the shield segments and thesusceptor.

Further embodiments of the disclosure are directed to susceptorassemblies comprising a susceptor with a top surface and a bottomsurface. The top surface has a plurality of recesses formed therein. Therecesses are sized to support a substrate during processing. A heater ispositioned below the susceptor to heat the susceptor. A shield ispositioned between the bottom surface of the susceptor and the heater.The shield increases deposition uniformity across the susceptor. Theshield has a ring shape with an inner edge and an outer edge. The inneredge is closer to a center of the susceptor than the outer edge. Theshield includes a plurality of protrusions extending inwardly from theinner edge, each protrusion having an opening therethrough. The distancefrom the inner edge of the shield to the outer edge of the shield coversat least about ⅔ of a width of the recess. A plurality of suspensionrods connects to the susceptor and supports the shield and maintains agap between the shield and the susceptor. Each of the suspension rodspass through an opening in the shield.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 shows a cross-sectional view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 2 shows a partial perspective view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 3 shows a schematic view of a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 4 shows a schematic view of a portion of a wedge shaped gasdistribution assembly for use in a batch processing chamber inaccordance with one or more embodiment of the disclosure;

FIG. 5 shows a schematic view of a batch processing chamber inaccordance with one or more embodiment of the disclosure; and

FIG. 6 shows a side view of a susceptor assembly in accordance with oneor more embodiment of the disclosure;

FIG. 7 shows a susceptor assembly in accordance with one or moreembodiment of the disclosure;

FIG. 8 shows a susceptor assembly in accordance with one or moreembodiment of the disclosure; and

FIG. 9 shows a susceptor assembly in accordance with one or moreembodiment of the disclosure.

DETAILED DESCRIPTION

Before describing several exemplary embodiments of the disclosure, it isto be understood that the disclosure is not limited to the details ofconstruction or process steps set forth in the following description.The disclosure is capable of other embodiments and of being practiced orbeing carried out in various ways.

A “substrate” as used herein, refers to any substrate or materialsurface formed on a substrate upon which film processing is performedduring a fabrication process. For example, a substrate surface on whichprocessing can be performed include materials such as silicon, siliconoxide, strained silicon, silicon on insulator (SOI), carbon dopedsilicon oxides, amorphous silicon, doped silicon, germanium, galliumarsenide, glass, sapphire, and any other materials such as metals, metalnitrides, metal alloys, and other conductive materials, depending on theapplication. Substrates include, without limitation, semiconductorwafers. Substrates may be exposed to a pretreatment process to polish,etch, reduce, oxidize, hydroxylate, anneal and/or bake the substratesurface. In addition to film processing directly on the surface of thesubstrate itself, in the present disclosure, any of the film processingsteps disclosed may also be performed on an under-layer formed on thesubstrate as disclosed in more detail below, and the term “substratesurface” is intended to include such under-layer as the contextindicates. Thus for example, where a film/layer or partial film/layerhas been deposited onto a substrate surface, the exposed surface of thenewly deposited film/layer becomes the substrate surface.

As used in this specification and the appended claims, the terms“precursor”, “reactant”, “reactive gas” and the like are usedinterchangeably to refer to any gaseous species that can react with thesubstrate surface.

Some embodiments of the disclosure are directed to processes ofdepositing a spacer material using a batch processing chamber, alsoreferred to as a spatial processing chamber. FIG. 1 shows across-section of a processing chamber 100 including a gas distributionassembly 120, also referred to as injectors or an injector assembly, anda susceptor assembly 140. The gas distribution assembly 120 is any typeof gas delivery device used in a processing chamber. The gasdistribution assembly 120 includes a front surface 121 which faces thesusceptor assembly 140. The front surface 121 can have any number orvariety of openings to deliver a flow of gases toward the susceptorassembly 140. The gas distribution assembly 120 also includes an outeredge 124 which in the embodiments shown, is substantially round.

The specific type of gas distribution assembly 120 used can varydepending on the particular process being used. Embodiments of thedisclosure can be used with any type of processing system where the gapbetween the susceptor and the gas distribution assembly is controlled.While various types of gas distribution assemblies can be employed(e.g., showerheads), embodiments of the disclosure may be particularlyuseful with spatial gas distribution assemblies which have a pluralityof substantially parallel gas channels. As used in this specificationand the appended claims, the term “substantially parallel” means thatthe elongate axis of the gas channels extend in the same generaldirection. There can be slight imperfections in the parallelism of thegas channels. In a binary reaction, the plurality of substantiallyparallel gas channels can include at least one first reactive gas Achannel, at least one second reactive gas B channel, at least one purgegas P channel and/or at least one vacuum V channel. The gases flowingfrom the first reactive gas A channel(s), the second reactive gas Bchannel(s) and the purge gas P channel(s) are directed toward the topsurface of the wafer. Some of the gas flow moves horizontally across thesurface of the wafer and out of the process region through the purge gasP channel(s). A substrate moving from one end of the gas distributionassembly to the other end will be exposed to each of the process gasesin turn, forming a layer on the substrate surface.

In some embodiments, the gas distribution assembly 120 is a rigidstationary body made of a single injector unit. In one or moreembodiments, the gas distribution assembly 120 is made up of a pluralityof individual sectors (e.g., injector units 122), as shown in FIG. 2.Either a single piece body or a multi-sector body can be used with thevarious embodiments of the disclosure described.

A susceptor assembly 140 is positioned beneath the gas distributionassembly 120. The susceptor assembly 140 includes a top surface 141 andat least one recess 142 in the top surface 141. The susceptor assembly140 also has a bottom surface 143 and an edge 144. The recess 142 can beany suitable shape and size depending on the shape and size of thesubstrates 60 being processed. In the embodiment shown in FIG. 1, therecess 142 has a flat bottom to support the bottom of the wafer;however, the bottom of the recess can vary. In some embodiments, therecess has step regions around the outer peripheral edge of the recesswhich are sized to support the outer peripheral edge of the wafer. Theamount of the outer peripheral edge of the wafer that is supported bythe steps can vary depending on, for example, the thickness of the waferand the presence of features already present on the back side of thewafer.

In some embodiments, as shown in FIG. 1, the recess 142 in the topsurface 141 of the susceptor assembly 140 is sized so that a substrate60 supported in the recess 142 has a top surface 61 substantiallycoplanar with the top surface 141 of the susceptor 140. As used in thisspecification and the appended claims, the term “substantially coplanar”means that the top surface of the wafer and the top surface of thesusceptor assembly are coplanar within ±0.2 mm. In some embodiments, thetop surfaces are coplanar within 0.5 mm, ±0.4 mm, ±0.35 mm, ±0.30 mm,±0.25 mm, ±0.20 mm, ±0.15 mm, ±0.10 mm or ±0.05 mm.

The susceptor assembly 140 of FIG. 1 includes a support post 160 whichis capable of lifting, lowering and rotating the susceptor assembly 140.The susceptor assembly may include a heater, or gas lines, or electricalcomponents within the center of the support post 160. The support post160 may be the primary means of increasing or decreasing the gap betweenthe susceptor assembly 140 and the gas distribution assembly 120, movingthe susceptor assembly 140 into proper position. The susceptor assembly140 may also include fine tuning actuators 162 which can makemicro-adjustments to susceptor assembly 140 to create a predeterminedgap 170 between the susceptor assembly 140 and the gas distributionassembly 120. In some embodiments, the heater is not part of thesusceptor assembly. In some embodiments, the heater is a separatecomponent from the susceptor assembly. In some embodiments, the heateris separate from the susceptor assembly and is configured to move alongwith the susceptor assembly to maintain a fixed distance between thesusceptor assembly and the heater.

In some embodiments, the gap 170 distance is in the range of about 0.1mm to about 5.0 mm, or in the range of about 0.1 mm to about 3.0 mm, orin the range of about 0.1 mm to about 2.0 mm, or in the range of about0.2 mm to about 1.8 mm, or in the range of about 0.3 mm to about 1.7 mm,or in the range of about 0.4 mm to about 1.6 mm, or in the range ofabout 0.5 mm to about 1.5 mm, or in the range of about 0.6 mm to about1.4 mm, or in the range of about 0.7 mm to about 1.3 mm, or in the rangeof about 0.8 mm to about 1.2 mm, or in the range of about 0.9 mm toabout 1.1 mm, or about 1 mm.

The processing chamber 100 shown in the Figures is a carousel-typechamber in which the susceptor assembly 140 can hold a plurality ofsubstrates 60. As shown in FIG. 2, the gas distribution assembly 120 mayinclude a plurality of separate injector units 122, each injector unit122 being capable of depositing a film on the wafer, as the wafer ismoved beneath the injector unit. Two pie-shaped injector units 122 areshown positioned on approximately opposite sides of and above thesusceptor assembly 140. This number of injector units 122 is shown forillustrative purposes only. It will be understood that more or lessinjector units 122 can be included. In some embodiments, there are asufficient number of pie-shaped injector units 122 to form a shapeconforming to the shape of the susceptor assembly 140. In someembodiments, each of the individual pie-shaped injector units 122 may beindependently moved, removed and/or replaced without affecting any ofthe other injector units 122. For example, one segment may be raised topermit a robot to access the region between the susceptor assembly 140and gas distribution assembly 120 to load/unload substrates 60.

Processing chambers having multiple gas injectors can be used to processmultiple wafers simultaneously so that the wafers experience the sameprocess flow. For example, as shown in FIG. 3, the processing chamber100 has four gas injector assemblies and four substrates 60. At theoutset of processing, the substrates 60 can be positioned between theinjector assemblies 30. Rotating 17 the susceptor assembly 140 by 45°will result in each substrate 60 which is between gas distributionassemblies 120 to be moved to an gas distribution assembly 120 for filmdeposition, as illustrated by the dotted circle under the gasdistribution assemblies 120. An additional 45° rotation would move thesubstrates 60 away from the injector assemblies 30. The number ofsubstrates 60 and gas distribution assemblies 120 can be the same ordifferent. In some embodiments, there are the same numbers of wafersbeing processed as there are gas distribution assemblies. In one or moreembodiments, the number of wafers being processed are fraction of or aninteger multiple of the number of gas distribution assemblies. Forexample, if there are four gas distribution assemblies, there are 4×wafers being processed, where x is an integer value greater than orequal to one. In an exemplary embodiment, the gas distribution assembly120 includes eight process regions separated by gas curtains and thesusceptor assembly 140 can hold six wafers.

The processing chamber 100 shown in FIG. 3 is merely representative ofone possible configuration and should not be taken as limiting the scopeof the disclosure. Here, the processing chamber 100 includes a pluralityof gas distribution assemblies 120. In the embodiment shown, there arefour gas distribution assemblies (also called injector assemblies 30)evenly spaced about the processing chamber 100. The processing chamber100 shown is octagonal; however, those skilled in the art willunderstand that this is one possible shape and should not be taken aslimiting the scope of the disclosure. The gas distribution assemblies120 shown are trapezoidal, but can be a single circular component ormade up of a plurality of pie-shaped segments, like that shown in FIG.2.

The embodiment shown in FIG. 3 includes a load lock chamber 180, or anauxiliary chamber like a buffer station. This chamber 180 is connectedto a side of the processing chamber 100 to allow, for example thesubstrates (also referred to as substrates 60) to be loaded/unloadedfrom the chamber 100. A wafer robot may be positioned in the chamber 180to move the substrate onto the susceptor.

Rotation of the carousel (e.g., the susceptor assembly 140) can becontinuous or intermittent (discontinuous). In continuous processing,the wafers are constantly rotating so that they are exposed to each ofthe injectors in turn. In discontinuous processing, the wafers can bemoved to the injector region and stopped, and then to the region 84between the injectors and stopped. For example, the carousel can rotateso that the wafers move from an inter-injector region across theinjector (or stop adjacent the injector) and on to the nextinter-injector region where the carousel can pause again. Pausingbetween the injectors may provide time for additional processing stepsbetween each layer deposition (e.g., exposure to plasma).

FIG. 4 shows a sector or portion of a gas distribution assembly 220,which may be referred to as an injector unit 122. The injector units 122can be used individually or in combination with other injector units.For example, as shown in FIG. 5, four of the injector units 122 of FIG.4 are combined to form a single gas distribution assembly 220. (Thelines separating the four injector units are not shown for clarity.)While the injector unit 122 of FIG. 4 has both a first reactive gas port125 and a second gas port 135 in addition to purge gas ports 155 andvacuum ports 145, an injector unit 122 does not need all of thesecomponents.

Referring to both FIGS. 4 and 5, a gas distribution assembly 220 inaccordance with one or more embodiment may comprise a plurality ofsectors (or injector units 122) with each sector being identical ordifferent. The gas distribution assembly 220 is positioned within theprocessing chamber and comprises a plurality of elongate gas ports 125,135, 145 in a front surface 121 of the gas distribution assembly 220.The plurality of elongate gas ports 125, 135, 145, 155 extend from anarea adjacent the inner peripheral edge 123 toward an area adjacent theouter peripheral edge 124 of the gas distribution assembly 220. Theplurality of gas ports shown include a first reactive gas port 125, asecond gas port 135, a vacuum port 145 which surrounds each of the firstreactive gas ports and the second reactive gas ports and a purge gasport 155.

With reference to the embodiments shown in FIG. 4 or 5, when statingthat the ports extend from at least about an inner peripheral region toat least about an outer peripheral region, however, the ports can extendmore than just radially from inner to outer regions. The ports canextend tangentially as vacuum port 145 surrounds reactive gas port 125and reactive gas port 135. In the embodiment shown in FIGS. 4 and 5, thewedge shaped reactive gas ports 125, 135 are surrounded on all edges,including adjacent the inner peripheral region and outer peripheralregion, by a vacuum port 145.

Referring to FIG. 4, as a substrate moves along path 127, each portionof the substrate surface is exposed to the various reactive gases. Tofollow the path 127, the substrate will be exposed to, or “see”, a purgegas port 155, a vacuum port 145, a first reactive gas port 125, a vacuumport 145, a purge gas port 155, a vacuum port 145, a second gas port 135and a vacuum port 145. Thus, at the end of the path 127 shown in FIG. 4,the substrate has been exposed to the first reactive gas 125 and thesecond reactive gas 135 to form a layer. The injector unit 122 shownmakes a quarter circle but could be larger or smaller. The gasdistribution assembly 220 shown in FIG. 5 can be considered acombination of four of the injector units 122 of FIG. 4 connected inseries.

The injector unit 122 of FIG. 4 shows a gas curtain 150 that separatesthe reactive gases. The term “gas curtain” is used to describe anycombination of gas flows or vacuum that separate reactive gases frommixing. The gas curtain 150 shown in FIG. 4 comprises the portion of thevacuum port 145 next to the first reactive gas port 125, the purge gasport 155 in the middle and a portion of the vacuum port 145 next to thesecond gas port 135. This combination of gas flow and vacuum can be usedto prevent or minimize gas phase reactions of the first reactive gas andthe second reactive gas.

Referring to FIG. 5, the combination of gas flows and vacuum from thegas distribution assembly 220 form a separation into a plurality ofprocess regions 250. The process regions are roughly defined around theindividual gas ports 125, 135 with the gas curtain 150 between 250. Theembodiment shown in FIG. 5 makes up eight separate process regions 250with eight separate gas curtains 150 between. A processing chamber canhave at least two process region. In some embodiments, there are atleast three, four, five, six, seven, eight, nine, 10, 11 or 12 processregions.

During processing a substrate may be exposed to more than one processregion 250 at any given time. However, the portions that are exposed tothe different process regions will have a gas curtain separating thetwo. For example, if the leading edge of a substrate enters a processregion including the second gas port 135, a middle portion of thesubstrate will be under a gas curtain 150 and the trailing edge of thesubstrate will be in a process region including the first reactive gasport 125.

A factory interface 280, which can be, for example, a load lock chamber,is shown connected to the processing chamber 100. A substrate 60 isshown superimposed over the gas distribution assembly 220 to provide aframe of reference. The substrate 60 may often sit on a susceptorassembly to be held near the front surface 121 of the gas distributionplate 120. The substrate 60 is loaded via the factory interface 280 intothe processing chamber 100 onto a substrate support or susceptorassembly (see FIG. 3). The substrate 60 can be shown positioned within aprocess region because the substrate is located adjacent the firstreactive gas port 125 and between two gas curtains 150 a, 150 b.Rotating the substrate 60 along path 127 will move the substratecounter-clockwise around the processing chamber 100. Thus, the substrate60 will be exposed to the first process region 250 a through the eighthprocess region 250 h, including all process regions between.

Embodiments of the disclosure are directed to processing methodscomprising a processing chamber 100 with a plurality of process regions250 a-250 h with each process region separated from an adjacent regionby a gas curtain 150. For example, the processing chamber shown in FIG.5. The number of gas curtains and process regions within the processingchamber can be any suitable number depending on the arrangement of gasflows. The embodiment shown in FIG. 5 has eight gas curtains 150 andeight process regions 250 a-250 h.

A plurality of substrates 60 are positioned on a substrate support, forexample, the susceptor assembly 140 shown FIGS. 1 and 2. The pluralityof substrates 60 are rotated around the process regions for processing.Generally, the gas curtains 150 are engaged (gas flowing and vacuum on)throughout processing including periods when no reactive gas is flowinginto the chamber.

Accordingly, one or more embodiments of the disclosure are directed toprocessing methods utilizing a batch processing chamber like that shownin FIG. 5. A substrate 60 is placed into the processing chamber whichhas a plurality of sections 250, each section separated from adjacentsection by a gas curtain 150.

Some embodiments of the disclosure incorporate dynamic IR shieldsattached to the bottom surface of the susceptor and are rotated with thesusceptor to create a permanent coverage under the wafer in areas ofinterest. Varying the shape of the shield can be used to modulate localtemperatures on the wafer surface facing the showerhead. In someembodiments the shield is suspended from the bottom of the susceptor viaa threaded fastener with locating features. Spacing between the shieldand the susceptor can vary to further impact temperature distribution.The shield materials may also be selected in such a way that impactwafer temperature distribution.

Referring to FIG. 6, one or more embodiment of the disclosure isdirected to susceptor assemblies 600. The susceptor assemblies 600comprise a susceptor 610 with a top surface 612 and a bottom surface614. A plurality of recesses 642 are formed in the top surface 612 ofthe susceptor 610. The recesses 642 are sized to support a substrate (orwafer) during processing. The recess 642 shown in FIG. 6 includes anouter peripheral ledge 644 to support an outer edge of the wafer.However, those skilled in the art will understand that the recess 642can have a flat bottom, like that illustrated in FIG. 1. The outerperipheral ledge 644 is merely one possible configuration for the recess642.

A heater 620 is positioned below the susceptor 610 to heat the susceptor610. The heater 620 can be any suitable type of heater including, butnot limited to, radiant heaters that emit infrared (IR) radiation toheat the bottom surface 614 of the susceptor 610. In some embodiments,the heater 620 is not part of the susceptor assembly 600 and is separatefrom the susceptor 610. In some embodiments, the heater is a separatecomponent from the susceptor assembly. In some embodiments, the heater620 is an infrared heater. In some embodiments, the heater 620 is not aninduction heater.

A shield 630 is positioned between the bottom surface 614 of thesusceptor 610 and the heater 620. The shield 630 has a top surface 632facing the bottom surface 614 of the susceptor and a bottom surface 634facing the heater 620. The shield 630 increases deposition uniformityacross the recesses 642 of the susceptor 610. In some embodiments, theshield 630 increases deposition uniformity and decreases temperatureuniformity across the recesses 642, and across the substrate.

FIGS. 7-9 show embodiments of the susceptor assembly 600. Each of theseembodiments is shown looking at the bottom surface 614 of the susceptor610. The recesses 642 and ledge 644 are drawn dotted lines to show thelocation of the recesses on the non-visible side of the susceptor 610.The recesses 642 are shown in this manner to illustrate the relativelocations of the recesses and the shields.

In the embodiment of FIG. 7, the shield 630 comprises a plurality ofshield segments 631. Each segment 631 is positioned in a region betweenrecesses 642 in the top surface of the susceptor 610. Each of the shieldsegments 631 in FIG. 7 is wedge-shaped extending radially from a center161 of the susceptor 610 toward an outer peripheral edge 144 of thesusceptor 610. The shield segments 631 shown do not overlap with therecesses 642 but it will be understood by those skilled in the art thatthere can be some overlap. In some embodiments, the shield 630 does nothave a continuous shield surface that blocks direct line of sightbetween the heater 620 and the bottom surface 614 of the susceptor. Insome embodiments, the shield segments are positioned decrease a localtemperature of the susceptor to improve temperature uniformity.

FIG. 8 shows another embodiment of the disclosure in which there are todifferent types of shield segments 631. The first segments 661 arecontoured to have a shape similar to the shape of the recesses 642. Thecontoured regions 662 shown are rounded to mimic the shape of therecesses 642 adjacent that contoured regions 662.

In some embodiments, the shield segments 661 are shaped to cover more ofthe leading edge 647 of the recess 642 than the trailing edge 548 of theadjacent recess 642. Without being bound by any particular theory ofoperation, it is believed that the rotation of the susceptor 610 dragsthe process gases between the regions and that the leading edge 647 isexposed to a higher concentration of process gases. The shielding isbelieved to decrease the relative temperature near the leading edge sothat the deposition is consistent with the center and trailing edge ofthe substrate, which is maintained at a higher temperature but with alower local reactive gas concentration.

The second type of shield segments 671 shown in FIG. 8 are aligned withthe recesses 642 to overlap. As used in this regard, the term “overlap”means that the vertical positioning of the recesses and the shieldsegments are aligned. Those skilled in the art will understand that theshield segments are not located physically over the recesses. The shieldsegments 671 extend from a region inside the inner edge 649 of therecess 642 toward a center 651 of the recess 642. The shield segment 671can extend less than the center 651, to the center 651 or beyond thecenter 651 of the recess 642.

In some embodiments, the shield segments 661 are present without shieldsegments 671. In some embodiments, shield segments 671 are presentwithout shield segments 661. In some embodiments, both shield segment661 and shield segment 671 are present.

FIG. 9 shows another embodiment of the susceptor assembly 600 in whichthe shield 630 is ring shaped. The ring has an inner edge 681 and anouter edge 682. The inner edge 681 is closer to the center 161 of thesusceptor 610 than the outer edge 682.

In some embodiments, the inner edge 681 of the shield 630 is positionedwithin a first quarter of a width of the recess 642. As used in thisregard, the width of the recess 642 is defined as the distance from thepoint of the recess closest to the center 161 of the susceptor to thepoint of the recess furthest from the center 161 of the susceptor. Thecenter of the recess 642 is at 50% of the width of the recess. In someembodiments, the inner edge 681 of the shield 630 is positioned withinthe inner 40%, 35%, 30%, 25%, 20%, 15%, 10% or 5% of the width of therecess. In some embodiments, the inner edge 681 is located outside thebounds of the recess closer to the center of the susceptor.

In some embodiments, the outer edge 682 of the shield 630 is positionedwithin a second half of the width of the recess 642. In someembodiments, the outer edge 682 of the shield 630 is positioned withinthe outer 40%, 35%, 30%, 25%, 20%, 15%, 10% or 5% of the width of therecess. Stated differently, in some embodiments, the outer edge 682 ofthe shield 630 is positioned at a point greater than or equal to about60%, 65%, 70%, 75%, 80%, 85%, 90% or 95% of the width of the recess. Insome embodiments, the outer edge 682 of the shield 630 is locatedoutside the outer edge of the recess.

In some embodiments, the inner edge of the shield is positioned withinthe first quarter (<25%) of the width of the recess and the outer edgeof the shield is positioned within a fourth quarter (>75%) of the widthof the recess. In some embodiments, the distance from the inner edge ofthe shield to the outer edge of the shield covers at least about ⅓, ½,or ⅔ of the width of the recess. In some embodiments, the distance fromthe inner edge of the shield to the outer edge of the shield covers atleast about 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65% of 70% of thewidth of the recess.

The shield 630 can be made from any suitable material. In someembodiments, the shield is made from one or more of stainless steel,aluminum oxide or aluminum nitride. In some embodiments, the shieldcomprises a dielectric material. In some embodiments, the shieldcomprises a ceramic material.

Referring again to FIG. 6, the shield 630 is positioned a distance fromthe bottom surface 614 of the susceptor 610 to form a gap G. In someembodiments, the gap G is in the range of about 0.25 mm to about 6 mm.In some embodiments, the gap G is greater than or equal to about 0.25mm, 0.5 mm, 0.75 mm, 1 mm, 1.5 mm, 2 mm or 2.5 mm. In some embodiments,the gap G is less than or equal to about 6 mm, 5.5, mm, 5 mm, 4.5 mm, 4mm or 3.5 mm. In some embodiments, the gap G is in the range of about 1mm to about 5 mm, or in the range of about 2 mm to about 4 mm, or in therange of about 2.5 mm to about 3.5 mm, or about 3 mm.

The heater 620 is spaced a distance D from the shield 630. In someembodiments, the heater 620 is spaced from the shield 630 a distance inthe range of about 30 mm to about 80 mm, or in the range of about 4 mmto about 70 mm. In some embodiments, the heater 620 and the shield 630are a distance apart greater than or equal to about 30 mm, 40 mm or 50mm. In some embodiments, the heater 620 is about 60 mm from the shield630. In some embodiments, the heater 620 is a separate component fromthe susceptor 610 or shield 630.

As shown in FIG. 6, in some embodiments, the susceptor assembly 600includes a plurality of suspension rods 695 connected to the susceptor610. The suspension rods 695 can support the shield 630 and maintaininga gap G between the shield 630 and the susceptor 610. The suspensionrods 695 can pass through an opening 690 in the shield 630. In someembodiments, each of the suspension rods 695 comprises a shoulder screw696 to connect the shield 630 to the suspension rod 695.

A controller 680 includes central processing unit (CPU) 682, memory 684,and support circuits 686. Central processing unit 682 may be one of anyform of computer processor that can be used in an industrial setting forcontrolling various chambers and sub-processors. Memory 684 is coupledto CPU 682 and may be one or more of readily available memory such asrandom access memory (RAM), read only memory (ROM), flash memory,compact disc, floppy disk, hard disk, or any other form of local orremote digital storage. Support circuits 686 are coupled to CPU 682 forsupporting CPU 682 in a conventional manner. These circuits may includecache, power supplies, clock circuits, input/output circuitry,subsystems, and the like.

In some embodiments, the controller includes a non-transitorycomputer-readable medium containing computer code that, when executed byoperation of one or more computer processors, performs an operation forcontrolling deposition processes in the chamber. The computer code caninclude instruction sets for the processor to enable the processor to,inter alia, control the heaters (power, temperature, position), heatshields, susceptor assembly rotation and lift and/or the gasdistribution assembly including gas flows.

The computer program code of some embodiments includes data modelsdefining acceptable levels within the chamber for each of a plurality ofgas types. The computer program code can include models or look-uptables to determine heater power settings for temperature control. Insome embodiments, the computer program code includes models to determineposition of one or more heat shields based on temperature feedbackcircuits.

In some embodiments, each shield segment 631, 661, 671 is supported byat least three suspension rods 695. In some embodiments, each shieldsegment 631, 661, 671 comprises at least three openings 690 to allow thesuspension rod to pass therethrough. As can be seen in FIGS. 7 and 8,some embodiments of the shield segments have three openings 690.

As shown in FIG. 9, some embodiments of the shield 630 include aplurality of protrusions 685 extending inwardly from the inner edge 681.The protrusions 685 can include an opening 690 to allow a suspension rodto pass therethrough. In some embodiments, the shield 630 is supportedby six suspension rods passing through six openings 690 in the shield630.

According to one or more embodiments, the substrate is subjected toprocessing prior to and/or after forming the layer. This processing canbe performed in the same chamber or in one or more separate processingchambers. In some embodiments, the substrate is moved from the firstchamber to a separate, second chamber for further processing. Thesubstrate can be moved directly from the first chamber to the separateprocessing chamber, or it can be moved from the first chamber to one ormore transfer chambers, and then moved to the separate processingchamber. Accordingly, the processing apparatus may comprise multiplechambers in communication with a transfer station. An apparatus of thissort may be referred to as a “cluster tool” or “clustered system,” andthe like.

Generally, a cluster tool is a modular system comprising multiplechambers which perform various functions including substratecenter-finding and orientation, annealing, annealing, deposition and/oretching. According to one or more embodiments, a cluster tool includesat least a first chamber and a central transfer chamber. The centraltransfer chamber may house a robot that can shuttle substrates betweenand among processing chambers and load lock chambers. The transferchamber is typically maintained at a vacuum condition and provides anintermediate stage for shuttling substrates from one chamber to anotherand/or to a load lock chamber positioned at a front end of the clustertool. Two well-known cluster tools which may be adapted for the presentdisclosure are the Centura® and the Endura®, both available from AppliedMaterials, Inc., of Santa Clara, Calif. However, the exact arrangementand combination of chambers may be altered for purposes of performingspecific steps of a process as described herein. Other processingchambers which may be used include, but are not limited to, cyclicallayer deposition (CLD), atomic layer deposition (ALD), chemical vapordeposition (CVD), physical vapor deposition (PVD), etch, pre-clean,chemical clean, thermal treatment such as RTP, plasma nitridation,anneal, orientation, hydroxylation and other substrate processes. Bycarrying out processes in a chamber on a cluster tool, surfacecontamination of the substrate with atmospheric impurities can beavoided without oxidation prior to depositing a subsequent film.

According to one or more embodiments, the substrate is continuouslyunder vacuum or “load lock” conditions, and is not exposed to ambientair when being moved from one chamber to the next. The transfer chambersare thus under vacuum and are “pumped down” under vacuum pressure. Inertgases may be present in the processing chambers or the transferchambers. In some embodiments, an inert gas is used as a purge gas toremove some or all of the reactants. According to one or moreembodiments, a purge gas is injected at the exit of the depositionchamber to prevent reactants from moving from the deposition chamber tothe transfer chamber and/or additional processing chamber. Thus, theflow of inert gas forms a curtain at the exit of the chamber.

The substrate can be processed in single substrate deposition chambers,where a single substrate is loaded, processed and unloaded beforeanother substrate is processed. The substrate can also be processed in acontinuous manner, similar to a conveyer system, in which multiplesubstrate are individually loaded into a first part of the chamber, movethrough the chamber and are unloaded from a second part of the chamber.The shape of the chamber and associated conveyer system can form astraight path or curved path. Additionally, the processing chamber maybe a carousel in which multiple substrates are moved about a centralaxis and are exposed to deposition, etch, annealing, cleaning, etc.processes throughout the carousel path.

During processing, the substrate can be heated or cooled. Such heatingor cooling can be accomplished by any suitable means including, but notlimited to, changing the temperature of the substrate support andflowing heated or cooled gases to the substrate surface. In someembodiments, the substrate support includes a heater/cooler which can becontrolled to change the substrate temperature conductively. In one ormore embodiments, the gases (either reactive gases or inert gases) beingemployed are heated or cooled to locally change the substratetemperature. In some embodiments, a heater/cooler is positioned withinthe chamber adjacent the substrate surface to convectively change thesubstrate temperature.

The substrate can also be stationary or rotated during processing. Arotating substrate can be rotated continuously or in discreet steps. Forexample, a substrate may be rotated throughout the entire process, orthe substrate can be rotated by a small amount between exposures todifferent reactive or purge gases. Rotating the substrate duringprocessing (either continuously or in steps) may help produce a moreuniform deposition or etch by minimizing the effect of, for example,local variability in gas flow geometries.

In atomic layer deposition type chambers, the substrate can be exposedto the first and second precursors either spatially or temporallyseparated processes. Temporal ALD is a traditional process in which thefirst precursor flows into the chamber to react with the surface. Thefirst precursor is purged from the chamber before flowing the secondprecursor. In spatial ALD, both the first and second precursors aresimultaneously flowed to the chamber but are separated spatially so thatthere is a region between the flows that prevents mixing of theprecursors. In spatial ALD, the substrate is moved relative to the gasdistribution plate, or vice-versa.

In embodiments, where one or more of the parts of the methods takesplace in one chamber, the process may be a spatial ALD process. Althoughone or more of the chemistries described above may not be compatible(i.e., result in reaction other than on the substrate surface and/ordeposit on the chamber), spatial separation ensures that the reagentsare not exposed to each in the gas phase. For example, temporal ALDinvolves the purging the deposition chamber. However, in practice it issometimes not possible to purge the excess reagent out of the chamberbefore flowing in additional regent. Therefore, any leftover reagent inthe chamber may react. With spatial separation, excess reagent does notneed to be purged, and cross-contamination is limited. Furthermore, alot of time can be used to purge a chamber, and therefore throughput canbe increased by eliminating the purge step.

Reference throughout this specification to “one embodiment,” “certainembodiments,” “one or more embodiments” or “an embodiment” means that aparticular feature, structure, material, or characteristic described inconnection with the embodiment is included in at least one embodiment ofthe disclosure. Thus, the appearances of the phrases such as “in one ormore embodiments,” “in certain embodiments,” “in one embodiment” or “inan embodiment” in various places throughout this specification are notnecessarily referring to the same embodiment of the disclosure.Furthermore, the particular features, structures, materials, orcharacteristics may be combined in any suitable manner in one or moreembodiments.

Although the disclosure herein has been described with reference toparticular embodiments, it is to be understood that these embodimentsare merely illustrative of the principles and applications of thepresent disclosure. It will be apparent to those skilled in the art thatvarious modifications and variations can be made to the method andapparatus of the present disclosure without departing from the spiritand scope of the disclosure. Thus, it is intended that the presentdisclosure include modifications and variations that are within thescope of the appended claims and their equivalents.

What is claimed is:
 1. A susceptor assembly comprising: a susceptor witha top surface and a bottom surface, the top surface having a pluralityof recesses formed therein, the recesses sized to support a substrateduring processing; a heater positioned below the susceptor to heat thesusceptor; and a shield positioned between the bottom surface of thesusceptor and the heater, the shield increasing deposition uniformityacross the susceptor.
 2. The susceptor assembly of claim 1, wherein theshield comprises a plurality of shield segments, each segment positionedin a region between recesses.
 3. The susceptor assembly of claim 2,wherein each of the shield segments is wedge-shaped extending radiallyfrom a center of the susceptor.
 4. The susceptor assembly of claim 2,wherein each of the shield segments is contoured to have a shape similarto a shape of the recesses.
 5. The susceptor assembly of claim 4,wherein the shield segments cover more of a leading edge of a recessthan a trailing edge of an adjacent recess.
 6. The susceptor assembly ofclaim 2, wherein each of the shield segments is aligned with a recessand extends from a region inside an inner edge of a recess toward acenter of the recess.
 7. The susceptor assembly of claim 1, wherein theshield is ring shaped with an inner edge and an outer edge, the inneredge closer to a center of the susceptor than the outer edge.
 8. Thesusceptor assembly of claim 7, wherein the shield comprises a pluralityof protrusions extending inwardly from the inner edge.
 9. The susceptorassembly of claim 8, wherein at least some of the plurality ofprotrusions comprises an opening to allow a suspension rod to passtherethrough.
 10. The susceptor assembly of claim 7, wherein the inneredge of the shield is positioned within a first quarter of a width ofthe recess.
 11. The susceptor assembly of claim 7, wherein the outeredge of the shield is positioned within a second half of the width ofthe recess.
 12. The susceptor assembly of claim 7, wherein the inneredge of the shield is positioned within a first quarter of a width ofthe recess, and the outer edge of the shield is positioned within afourth quarter of the width of the recess.
 13. The susceptor assembly ofclaim 7, wherein the distance from the inner edge of the shield to theouter edge of the shield covers at least about ⅔ of a width of therecess.
 14. The susceptor assembly of claim 1, wherein the shield ismade from one or more of stainless steel, aluminum oxide or aluminumnitride.
 15. The susceptor assembly of claim 1, wherein the shield ispositioned a distance from the bottom surface of the susceptor to form agap in the range of about 0.25 mm to about 6 mm.
 16. The susceptorassembly of claim 15, wherein the heater is spaced in the range of about30 mm to about 80 mm from the shield.
 17. The susceptor assembly ofclaim 1, further comprising a plurality of suspension rods connected tothe susceptor, the suspension rods supporting the shield and maintaininga gap between the shield and the susceptor.
 18. The susceptor assemblyof claim 17, wherein each of the suspension rods comprises a shoulderscrew to connect the shield to the suspension rod.
 19. A susceptorassembly comprising: a susceptor with a top surface and a bottomsurface, the top surface having a plurality of recesses formed therein,the recesses sized to support a substrate during processing; a heaterpositioned below the susceptor to heat the susceptor; a shieldpositioned between the bottom surface of the susceptor and the heater,the shield comprising a plurality of shield segments, each shieldsegment positioned in a region between the recesses and increasingdeposition uniformity across the susceptor, each shield segment iscontoured to have a shape similar to a shape of the recesses and covermore of a leading edge of a recess than a trailing edge of an adjacentrecess, each shield segment including a plurality of openingstherethrough; and a plurality of suspension rods connected to thesusceptor and passing through the plurality of openings in the shieldsegments to support the shield segments and maintain a gap between theshield segments and the susceptor.
 20. A susceptor assembly comprising:a susceptor with a top surface and a bottom surface, the top surfacehaving a plurality of recesses formed therein, the recesses sized tosupport a substrate during processing; a heater positioned below thesusceptor to heat the susceptor; and a shield positioned between thebottom surface of the susceptor and the heater, the shield increasingdeposition uniformity across the susceptor, the shield having a ringshape with an inner edge and an outer edge, the inner edge closer to acenter of the susceptor than the outer edge, the shield including aplurality of protrusions extending inwardly from the inner edge, eachprotrusion having an opening therethrough, the distance from the inneredge of the shield to the outer edge of the shield covers at least about⅔ of a width of the recess; and a plurality of suspension rods connectedto the susceptor, the suspension rods supporting the shield andmaintaining a gap between the shield and the susceptor, each of thesuspension rods passing through an opening in the shield.